Jet propulsion pump assembly

ABSTRACT

A jet propulsion pump assembly is provided with wear-ring of non-metallic material such as plastic, the wear-ring being installed so as to be worn in by rotation of the impeller when under load. Provision is made for reducing thrust on the impeller.

United States Patent [191 Woell, Jr.

[ 1 Sept. 4, 1973 JET PROPULSION PUMP ASSEMBLY [75] Inventor: Fred T.Woell, Jr., Little Rock, Ark.

[73] Assignee: Jacuzzi Bros., Inc., Little Rock, Ark.

[22] Filed: Dec. 17, 1971 [21] Appl. No.: 209,138

[52] US. Cl 415/174, 415/104, 60/221, 277/137 [51] Int. Cl. F0411 29/08,F01d 3/00 [58] Field of Search 415/501, 174; 277/137; 60/200, 221, 222

[56] References Cited UNITED STATES PATENTS 3,405,526 10/1968 Aschauer60/221 3,227,418 1/1966 West 415/l74 3,249,083 5/1966 lrgens 60/2213,250,069 5/1966 Rhoda 3,603,599 9/1971 Laird 3,656,862 4/1972 Rahaim etal 4l5/l74 Primary Examiner-Henry F. Raduazo AttorneyEdward Brosler [57]1 ABSTRACT A jet propulsion pump assembly is provided with wearring ofnon-metallic material such as plastic, the wearring being installed soas to be worn in by rotation of the impeller when under load. Provisionis made for reducing thrust on the impeller.

4 Claims, 4 Drawing Figures "m xp PATENTEDSEFJIQTS sm-Ii 1 M2 INVENTORFRED T. WOELL, JR. BY

ATTORNEY PAIENIEB E 3.756.741

VII/A I NVEN TOR.

FRED T. WOELL, JR.

ATTORNEY JET PROPULSION PUMP ASSEMBLY The invention relates to jetpropulsion pump assemblies and more particularly to wear problemsconnected therewith.

Jet propulsion pump assemblies have previously embodied a suction piece,a bowl, and a wear-ring installed between the suction piece and bowl byfasteners, the wear-ring facing the impeller within the bowl and havingan internal surface contoured to the surface generated by the peripheraledges of the impeller blades.

During operation of the pump, the impeller blades become loaded, byreason of which, a certain degree of deflection occurs. Accordingly, aslight initial spacing between the edges and the wear-ring during aquiescent condition of the pump, may not be adequate enough to allow forsuch deflection during loading, with the result that the wear-ring mightgall or ball up, or the impeller could conceivably jam or freeze,particularly should a stone or large gravel find its way into the pump.

Further, the manner of installing the wear-ring into the pump assemblyby use of fasteners, created a problem of replacement of the wear-ring,when and if such replacement became necessary. The loading of theimpeller during operation, furthermore, results in a thrust which thrustis taken up by a thrust bearing. Such thrust has, to a degree, beenreduced in the past, by providing a passage through the impeller fromthe suction side to the pressure side, which passage thereby exposed thehigh pressure side of the impeller to the low pressure on the suctionside.

A simpler solution toward reducing such thrust is desir-,

able.

Among the objects of the present invention are:

1. To provide a novel and improved jet pump assemy;

2. To provide a novel and improved jet pump assembly in which galling orballing up of the wear-ring is atfectively eliminated;

3. To provide a novel and improved jet pump assembly wherein reductionof thrust on the discharge end of the impeller is achieved in a novelmanner;

4. To provide a novel and improved jet pump assembly wherein thewear-ring may be installed or replaced simply and quickly;

5. To provide a novel and improved wear-ring for a jet pump assembly;and

6. To provide a novel and improvedmethod-of installing a wear-ring in ajet pump assembly.

Additional objects of the invention will be brought out in the followingdescription of a preferred embodiment of the same, taken in conjunctionwith the accompanying drawings wherein,

FIG. I is a general view in phantom through a-jet pump assembly in whichthe present invention is incorporated;

FIG. 2 is an enlarged view in section through the impeller and nozzleportion of the jet pump assembly of FIG. 1, taken in the planes 2-2 ofFIG. 3;

FIG. 3 is a view in sectiontaken in the plane 3-3 of FIG. 2, with theimpeller removed; and

FIG. 4 is a view in section taken through the thrust bearing region ofthe jet pump assembly of FIG. 1.

Referring to the drawings for details of the invention in its preferredform the jet pump assembly depicted in FIG. 1, involves a suction piece1, a bowl 3 bolted thereto and terminating in a jet nozzle 5, thesuction piece curving downwardly to the bottom of the boat in which itis to be installed, where it is exposed to the water beneath the boatfor intake to the pump.

An impeller 7 within the bowl is mounted on a shaft 9 which is supportedat the discharge side of the impeller in a generally conical shaped hub11 symmetrically located in the bowl and nozzle by radial vanes 13 whichserves the added function of stabilizing flow of water from the impellerto the nozzle.

At its other end, the impeller shaft is supported in a thrust bearingassembly 17 installed in a housing 19 formed on the outer wall of thesuction piece, said bearing assembly including a bearing 18.

Where the suction piece and the bowl are joined, as by a plurality ofperipheral bolts 21, these two components are internally recessed toprovide for reception of a wear-ring 23, and a pair of opposingshoulders 25, 27,

between which the wear-ring may be clamped as the suction piece and bowlare bolted together.

To facilitate installation of the wear-ring and assure proper alignment,the wear-ring is provided with a plurality of peripherally spaced dowels29, preferably in the surface facing the suction piece, the dowels to bereceived in a corresponding number of holes similarly spaced about theperiphery of the suction piece.

Of considerable importance to the present invention, is the fact, thatthe wear-ring, instead of being fabricated of metal, in accordance withprior practice, is now fabricated of non-metallic material, andpreferably molded from plastic, such for example, as polypropylene, asit has been discovered that, should the blade edges of an impellerengage a wear-ring when made of such material, the material will eithergive or wear or both give and wear, and will not gall or ball up.

It has also been discovered that, when using such material, theaccidental introduction of a stone or large gravel between theperipheral edge of an impeller and the wear-ring, will not cause theimpeller to stall or freeze, as might conceivably be the case, were thewear-ring made of metal.

In a prior art conventional jet pump propulsion assembly, the edges ofthe impeller blades angle toward the intake side, and the suction pieceand bowl in the region of the impeller, will have their internalsurfaces correspondingly angled. Consequently the wear-ring will bemolded with its inner surface contoured to the substantially conicalsurface generated by the peripheral edges of the impeller blades when inrotation.

Because the impeller can now rotate without galling or balling up of thewear-ring when in contact with the wear-ring, the wear-ring is sodimensioned and the iminto a rotatably supported socket 31, and thethrust bearing housing 19 comprises a portion 33 integral with thesuction piece and an end portion 35 overlapping the socket, with theintervening space closed off by a seal 37, permitting limitedlongitudinal adjustment of this end portion. A retaining ring 39installed in the outer race of the bearing 18 extends between the twoportions of the housing.

By adding shims 41 between the fixed portion of the bearing housing andthe retaining ring, the impeller shaft and impeller can be adjustablyshifted to the right as viewed in FIGS. 2 and 4.

With an arrangement as described, the impeller is initially adjusted byinstalling the number of shims necessary to effect a wearing in of thewear-ring. In view of the nature of the wear-ring material the initialadjustment should suffice, but should a subsequent adjustment be deemednecessary, additional shims may be added to accomplish such subsequentadjustment.

To reduce thrust on the thrust bearing via the impeller, the hub 11 isrecessed adjacent the pressure side of the impeller, such recess joininga plurality of cavities 43 formed in the hub, with each cavity flowconnected with a low pressure region in the nozzle by a connecting flowpassage 45 formed in the hub.

In the hub recess is disposed at shallow cup 47 of plastic or othersuitable non-metallic material, such shallow cup being secured bymachine screws 49 into the hub partitions 51 formed between thecavities.

The hub of the impeller is dimensioned to rotatably fit into thisshallow cup, thrust pressure being developed along the edge of the cup.Due to the flow connection established between the inside of the shallowcup and the low pressure region of the nozzle, a pressure differentialwill develop across that portion of the impeller hub entering theshallow cup. Inasmuch as the fit between the impeller hub and theshallow cup is a rotational fit and not a leak tight joint, a limitedflow of water will occur from the impeller hub to the nozzle via thechambers 43, thereby reducing the thrust against the impeller hub, witha consequent reduction in thrust against the thrust bearing.

While I have described the invention in its preformed form and inconsiderable detail, the same is subject to alteration and modificationwithout departing from the underlying principles involved, and Iaccordingly do not desire to be limited in my protection to the detailsset forth except as may be necessitated by the appended claims.

I claim:

1. In a jet propulsion pump assembly having a suction piece and a bowlterminating in a nozzle, a conical shaped hub support for an impellerassembly disposed axially of said bowl and connected to said bowl by aplurality of vanes to determine passages to said nozzle, a thrustbearing supported within said suction piece, an impeller assembly insaid bowl supported by and between said hub support and said thrustbearing, said impeller assembly including an impeller having blades withtheir remote edges such as to generate a substantially conical surfaceat an angle to the axis of said impeller, a wear-ring installed betweensaid suction piece and bowl in line with said blade edges, saidwear-ring having an interior surface contoured to the surface generatedby the remote edges of said impeller blades, and means for clamping saidwear-ring between said suction piece and said bowl with said interiorsurface in proximity to said blade edges, said clamping means beingindependent of said wear-ring.

2. In a jet propulsion pump assembly in accordance with claim 1,characterized by said wear-ring being of a non-metallic material.

3. In a jet propulsion pump assembly in accordance with claim 1,characterized by said wear-ring having a plurality of dowels extendingtherefrom in matching relationship to a plurality of holes in anadjacent component of said pump assembly, whereby said wear-ring mayreadily be assembled thereto, and removed therefrom for replacementuponunclamping of said independent clamping means.

4. In a jet propulsion pump in accordance with claim 1, characterized bysaid wear-ring being of plastic.

=0: a: a: :u

1. In a jet propulsion pump assembly having a suction piece and a bowlterminating in a nozzle, a conical shaped hub support for an impellerassembly disposed axially of said bowl and connected to said bowl by aplurality of vanes to determine passages to said nozzle, a thrustbearing supported within said suction piece, an impeller assembly insaid bowl supported by and between said hub support and said thrustbearing, said impeller assembly including an impeller having blades withtheir remote edges such as to generate a substantially conical surfaceat an angle to the axis of said impeller, a wear-ring installed betweensaid suction piece and bowl in line with said blade edges, saidwear-ring having an interior surface contoured to the surface generatedby the remote edges of said impeller blades, and means for clamping saidwear-ring between said suction piece and said bowl with said interiorsurface in proximity to said blade edges, said clamping means beingindependent of said wear-ring.
 2. In a jet propulsion pump assembly inaccordance with claim 1, characterized by said wear-ring being of anon-metallic material.
 3. In a jet propulsion pump assembly inaccordance with claim 1, characterized by said wear-ring having aplurality of dowels extending therefrom in matching relationship to aplurality of holes in an adjacent component of said pump assembly,whereby said wear-ring may readily be assembled thereto, and removedtherefrom for replacement upon unclamping of said independent clampingmeans.
 4. In a jet propulsion pump in accordance with claim 1,characterized by said wear-ring being of plastic.